


Full Alchemist

by MuscleChubBoi



Category: Fullmetal Alchemist - All Media Types, Fullmetal Alchemist: Brotherhood & Manga
Genre: Alchemy, Alchemy Mishaps, Alphonse is now a medical alchemist, Belly Kink, Eating, Ed is now a scientist, Edward Elric Swears, Fat - Freeform, Fat Edward Elric, Growth, It’s his new career after leaving the military, M/M, Medical Alchemy, More tags and characters to come, Musclechub Edward Elric, Muscles, Muscular Edward Elric, Post-Series, Stuffing, They live in a new house they built near where their old one once stood, Weight Gain, and a farmer to help support their research projects, musclechub, post-canon AU
Language: English
Status: In-Progress
Published: 2021-01-03
Updated: 2021-01-03
Packaged: 2021-03-13 15:48:44
Rating: Mature
Warnings: Creator Chose Not To Use Archive Warnings
Chapters: 1
Words: 2,440
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/28530969
Author URL: https://archiveofourown.org/users/MuscleChubBoi/pseuds/MuscleChubBoi
Summary: A few years after Father’s defeat, Amestris has recovered well and the Elric Brothers currently live peacefully in their hometown of Resembool. Little did they realize, one of Alphonse’s latest alchemy experiments would lead to BIG changes for Ed.
Relationships: Alphonse Elric & Edward Elric, Alphonse Elric & Winry Rockbell, Edward Elric & Winry Rockbell
Comments: 4
Kudos: 14





	Full Alchemist

**Author's Note:**

> Dedicated to my friends on Tumblr who helped inspire this. ;)
> 
> NOTE: This is a Weight Gain and Muscle Kink fic. Don’t like? Don’t read. This is your final notice.

Finally! It was ready! Alphonse practically vibrated with nervous energy as he looked upon his newly set up circle and ingredients within it. If this new formula reacted as he hoped, it would revolutionize healthcare and medical alchemy for generations to come!  
  
At least that’s what Alphonse hoped.  
Success in his latest endeavor would mean a revolution in medical alchemy practice, a now booming field under Fuhrer Mustang’s administration. Holistic treatment and immunization! Essentially a cure-all that would help make the people of Amestris healthier than ever!  
  
Al took a quick glance at the clock on his wall... Almost lunch time. Should be enough time to squeeze in one more experiment before he breaks for lunch.  
  
The young blond got into position at the edge of his alchemy circle, took a deep, stabilizing breath, and drew upon the alchemical tectonic energy he knew was waiting at the ready.  
  
Just as he was about to channel the energy through the circle, the door to the basement banged open and in stomped Edward. “Al, did ya not hear me!? I said lunch is ready!”  
  
“Wait, Big Brother! Don’t...!”, Alphonse cried just as the energy channeled through the circle and Ed accidentally stepped into it, not paying adequate attention to the floor beneath his feet.  
  
There was great surge of light, a flash, and a ***BANG*** as both brothers cried out! And then everything was still.  
  
“B-Big Brother? Are you there?”, Al whimpered to the now smoke-filled room. A loud grunt followed by a groan sounded off in the direction Ed had been standing before suddenly, a shape far too large to be Ed rose up in the dissipating smoke.  
  
Alphonse scooted back as the impossibly large silhouette rose higher and higher until its... Head, he guessed, nearly reached the basement ceiling. It coughed and replied, “Yeah, Al. I’m still here. What the hell just happened? I feel... Different.”  
  
The younger blond gasped loudly as the older stepped forward into the light to reveal that he was... ENORMOUS! Everything about the cantankerous blond was way bigger than it should be! Ed stood before him with large, thick, muscle-and apparently fat-bound limbs; wide shoulders and hips to match; big, pillowy pecs; and a now massive, round belly swelling out from underneath a too tiny shirt where flat abs once were. His pants were similarly strained, now far too short and many seams popped to accommodate all the new mass stretching them. However, the most shocking feature was the sheer, towering height the eldest Elric now possessed! He’s gigantic in every way!  
  
Ed looked at his brother’s pale, aghast face quizzically. “Al? Somethin’ wrong?”  
  
Alphonse raised a quivering finger to point at him, “B-B-Big!”, he stuttered, panicking.  
  
The now much bigger blond looked down at himself, “What the hell?”  
  
“I’m huge!”, Edward spread his thick, muscled arms and ogled them before cupping and squeezing his big pecs, then moved down and grabbed the sides of his now massive keg of a belly and shook it. He looked back at his now much wider and rounder rear. He lit up excitedly, “Wait a minute… I really am huge! Al! You made me bigger! Taller!”  
  
The elder Elric looked down to his little brother (Down! To Al!), whose face was flushed deeply from embarrassment at his brother’s shameless display. The younger Elric got his nerves together, “Uh… Um, yeah. I was experimenting with a new treatment for medical alchemy. Clearly I have more work to do.”  
  
“Ha! Are you kidding, lil’ bro? This is perfect. I’ve never felt better!” The elder blond flexed and stretched this way and that, striking various poses that accentuated his new musculature… And his exceptional girth. “In fact, I feel as strong as an ox!”  
  
He snorted with amusement and then pointed to his large belly, “And I even look like I ate one, too!” He cracked up at his own joke, his laughter filling the small basement.  
  
“Big Brother-”, Alphonse was about to speak up when he was interrupted by a deep, resonating growl he felt in his bones. Ed stopped laughing and clutched his gut, fingers sinking into thick fat, “Hold that thought, Al. I’m feeling really hungry all of a sudden… Oh yeah! Lunch!”  
  
With that, Ed quickly turned and took off, squeezing his way out of the basement door before trampling up the stairs with a _**THUMP THUMP THUMP**_. The racket was easy to follow as he made his way up, the stairs squealing and shrieking as though in pain while the walls creaked and cracked. Al sighed and set about cleaning up his lab as he heard a loud banging around coming from upstairs. How did he always end up in these situations? Mind you, he’d never turned his brother into a giant before, but the point still stands.  
  
Oh God! He’s turned his brother into a giant freak! How was he going to explain this to anyone? To Winry and Pinako? Does this count as human transmutation? Crap… He needs to find his book on those laws and figure out if he should hide his now literally big brother from the authorities. At least until he can fix this.  
  
Feeling less than confident about his situation, Al headed upstairs. He noticed, with mounting dread, that the house was quiet… Too quiet. The younger Elric rushed the rest of the way up and went to the kitchen… It was empty, though a platter was scattered with crumbs from now devoured sandwiches and the soup pot was empty and placed in the sink. Alphonse looked around, “Big Brother?”  
  
Then, he heard a loud grunting coming from outside, followed by a metallic clanking. Oh dear, what’s he up to now?  
  
Al emerged from the Elric residence to witness a sight that dropped his jaw: Edward on his back in the front yard, lifting their shared truck like a barbell from the army gymnasiums Ed frequented back when they were in the military. The younger brother couldn’t see his elder sibling’s face, as he was obscured by the enormous dome of his own gut, but judging from how even his grunting was and how steady his lifts were, the blond giant wasn’t straining, even under all the weight of the truck.  
  
Still, he doesn’t have Al to “spot” for him anymore… “Big Brother, please don’t get yourself hurt!”  
  
“Oh, hey, Al”, Edward grunted as he gently lowered the truck down before getting up. His belly shook and muscles flexed as he stretched and brushed off, “Just testing out my new strength! Did you need something?”  
  
“I didn’t need anything… I was just worried you might drop the truck on yourself.”  
  
The bigger blond smirked and then flexed his big arms, biceps bulging into huge peaks that shredded what was left of his already torn shirt sleeves. Wait… Had he gotten even bigger? “Really? Check out how strong my arms are now. You think I would drop a truck if I didn’t want to?”  
  
Alphonse gulped, “I’m sure you’re VERY strong, Big Brother, but you still shouldn’t-“  
  
He was interrupted once again by a deep, rumbling growl that emanated from Edward’s belly. “Damn! Hungry again already!? I’m gonna need to get more groceries soon with this new appetite! I just can’t keep this thing full, it seems!”, the burly blond smacked the side of his huge gut with apparent pride and chuckled gleefully.  
  
Ed walked right past Al and squeezed his way through the front door back into the house, the doorframe cracked ominously as his girth was forced through. The younger blond followed his brother inside to find him already in the kitchen, rifling through the cupboards and the refrigerator. He was swallowing food and guzzling drinks with gusto, the room filled with the sounds of his loud eating. Al watched his brother pig out, stunned. Sure, Ed was a big eater before but this level of gluttony… It’s practically unhinged.  
  
And it almost seems like Ed is growing more while he eats…  
  
As if in confirmation, the buttons that remained on Ed’s shirt all popped off and ricocheted off the walls in sequence while Ed gulped down a bottle of orange juice. Ed didn’t seem to notice or care, and Alphonse is certainly under the impression that his brother might actually be enjoying this accident a little too much. Best not to tell him he’s still getting bigger… Al’s more than aware of how Ed feels about his normal, diminutive height even after his last growth spurt. If he learns now about his continual growing, he might do something crazy before Al can return him to normal.  
  
“Al.”  
  
Alphonse jerked to attention as Ed handed him a couple of sandwiches, “Sorry about eating all of lunch earlier. I was so hungry, I kind of lost track of how much I was having!” The elder laughed and returned to his gorging.  
  
“It’s fine, big brother. I understand.”, he replied before biting into a sandwich, watching with morbid fascination as Ed ate the entire remaining three-fourths of a cake he’d made for dessert last night, before moving on to some fruit. There was no doubt about it, he observed to himself, Ed was slowly but surely swelling bigger and bigger as he ate. His muscles were thickening and bulging more and more as well.  
  
When the big blond finished off a few bottles of his favorite soda, he froze as he dropped the last one. A low rumbling could be heard emanating from his belly before he opened his mouth wide and unleashed a loud, deep belch that rattled the windows. “Damn, excuse me!”, Edward chuckled, laughing at Alphonse’s mortified expression.  
  
“Al”, he giggled, “you should see the look on your face!”  
  
The younger Elric blushed, “Hush, Big Brother! I just wasn’t expecting that!”  
  
“I’ll be honest, I wasn’t either.” The amused blond grunted and got up, his head now pretty much touching the ceiling. He yawned widely, making his jaw pop, “I think I’m gonna go to the living room and take a nap.”  
  
Al nodded as Ed made his way past him, the younger brother going and grabbing a drink from the fridge when he heard a loud cracking and groan behind him. “Uh… Hey, Al. Can I get a little help here? I think I might’ve eaten too much.”  
  
He spun around to witness the spectacle of his brother squirming to get loose from the apparent vice grip the kitchen doorway had on his sides. The big blond’s girthy middle was trying to squeeze through, but was too wide. How his equally broad shoulders got through fine, Al had no idea. “Big Brother! Umm… What should I do?”  
  
“Just kinda help push me through, if you would!”  
  
“Uh”, Alphonse looked at the only available place to push against… His brother’s gigantic, barely clothed rear. “Are you sure?”  
  
“Yes I’m sure! I wouldn’t ask otherwise!”  
  
The smaller male blushed a deep scarlet as he approached and gently placed his hands on one of his brother’s large, pillowy cheeks. His hands sunk into the fat a little ways before hitting what he could only presume was the solid mound of muscle underneath. Why did he always end up in weird situations like this?  
  
Ed called back to him, “Alright, now help me push through on three! One… Two… Three!”  
  
Bracing himself against the floor, Al shoved with all the strength of his body, while Ed used his mighty arms and legs to simultaneously pull and push himself through. With a loud creak, he popped loose for a brief second before coming to a halt again. “Shit… Al, I think my hips are stuck. Gonna need you to push again.”  
  
Alphonse rolled his eyes. Of course. He braced himself against Ed with his shoulder and shoved against his rear even harder than before, Edward also straining so much he was shuddering with the effort.  
  
Suddenly, with a loud ***CRACK*** the big blond broke loose from the doorway and landed on his stomach with an “Oof!”  
  
The smaller blond barely caught himself on the now broken doorway, which he stared at with wide eyes. Ed got up with a smile, said his thanks and headed across the house to the living room. Al followed him and found him already plopped down on the rug that dominated the floor of the room, leaning back against the sofa and watching their new television.  
  
“TV” as people had taken to calling it was a relatively recent development that had only just come out on the market commercially. Ed had splurged some of his military retirement pension on one after witnessing a demonstration of the technology at an exhibition in Central. Already, there was a decent array of hourly and half-hourly programs and news bulletins running from 8:00 to 20:00 every day. And Ed himself was very fond of the device.  
  
Alphonse stepped in front of the television. “Big Brother, I think I could probably return you back to normal, if I can figure out the proper formula.”  
  
“Nah.”  
  
The younger brother blinked at his elder’s dismissal. “Huh? What do you mean ‘Nah’?”  
  
“Exactly what you think it means.”, Ed replied. “Aside from that minor inconvenience with the kitchen door, I feel great! I’m stronger than I’ve ever been before and even this-“, he patted his large, round belly dominating his lap, “is starting to grow on me!”  
  
He chuckled as Alphonse groaned, “Big Brother, are you sure?”  
  
“Of course I’m sure! Al, you know I’ve always dreamed of being bigger and taller and now you’ve given me that, even if this wasn’t what I originally imagined. I don’t want to go back to normal when I know this is a possibility. Thank you for your concern and thank you for this.” He gestured to himself and grinned, “But I’ll be fine! You go and continue your experiments. Find that big breakthrough you’re always talking about!”  
  
Alphonse sighed and left the living room. He stopped before heading down to the basement again… He should go talk to Winry. She’ll need to know what’s going on. The last thing he needed in the morning was her waltzing in and screaming at the sight of his enormous brother. Plus, she might be able to convince Ed to see reason… Things might not end well if the wrong person sees him, considering the laws against human transmutation are even more strict nowadays than ever before.  
  
Another loud belch rattled the pictures on the wall next to him. “Ha! Excuse me again!”, Ed called from the living room.  
  
Yeah, he definitely needs to have a chat with Winry.

**Author's Note:**

> Hope y’all who read this enjoyed it! There’s more to come in the near future! And it’ll get a lot more fun too. ;)
> 
> Let me know what you think. Kudos and comments are greatly appreciated and constructive criticism helps let me know how to improve my writing!


End file.
